Today in 2001, Wikipedia was launched. Since its creation, Wikipedia has grown rapidly into one of the largest reference websites, attracting nearly 78 million visitors monthly as of January 2010 about 80 million unique monthly visitors as of December 2010. There are more than 91,000 active contributors working on more than 17,000,000 articles in more than 270 languages. As of today, there are 3,528,909 articles in English.

In 2005, Jimmy Wales, Wikipedia’s founder, said: “[Wikipedia] should be thought of as a work in progress — it’s our intention to be Britannica or better quality, and our policies and everything are designed with that goal in mind. We don’t reach that quality yet — we know that. We’re a work in progress.”

Whenever Wikipedia is discussed (for example in this excellent BusinessWeek article), the question of its “inaccuracies” comes up. Here’s some anecdotal evidence to the contrary: When I researched my recent post on the birth of the photography industry, I first read in both the 11th edition (1911) and the 15th edition (first printed 1974; my set is from 1989) of the Encyclopedia Britannica that Francois Arago presented the Daguerreotype process to the French Academy of Sciences on January 9th, 1839. Checking other, more specialized sources, I learned that the date was actually January 7th. Wikipedia, as opposed to the Britannica, has the correct date (for example, here and here).

Update: Wikipedia now has 408 million visitors (annually?), according to Jimmy Wales, and he is aiming to have 1 billion in 2015.